"At 01:25hrs on Saturday [00:25 GMT], 16 September, officers at Buckingham Palace responded to a person climbing the wall and entering the Royal Mews. Following a search, a 25-year-old man was detained by officers outside the stables in the Royal Mews. At no point did the man enter Buckingham Palace or the Palace Gardens," the Metropolitan Police said in a statement.
The man was detained under the UK's Serious Organised Crime and Police Act for trespassing on a protected site, the statement added.
The 25-year-old offender is currently in police custody.